1. Field of the Invention
The present invention relates to apparatus and methods useful in the spiral winding and cutting of paper tubes to form composite cans, and in particular, relates to apparatus and methods useful for removing foreign and undesirable materials from the can after the winding and cutting operations.
2. Description of the Prior Art
Numerous prior art patents suggest apparatus and methods for winding a strip of heavy paper into a tube around a mandrel winding and glueing a labeling strip onto the tube, and then cutting the tube into specified lengths. See, for example, U.S. Pat. Nos. 3,133,482 to Glassey and 2,712,778 to Robinson.
After the tube is cut into the prescribed length, each length is provided with a bottom, the container is filled with a consumable product (such as concentrated citrus juice, for example) and a removable top is affixed to the open end. This type of container is commonly referred to as a "composite can".
Many millions of such composite cans are required to satisfy the demands of the marketplace. Therefore, the manufacture of these cans must necessarily be accomplished at high production rates. Thus, a typical composite can tube winding machine will manufacture on the order of about one hundred and fifty thousand cans per shift.
As described in the above-mentioned patents, it is necessary to provide some means of indexing the cutting operation, in order to insure that each can is cut to the same prescribed length. Some commercially available composite can tube winding machines accomplish this by providing a so-called "trim ring" cutting operation wherein some cans are trimmed at one end to insure that all of the cans are of the same length. The result of this operation is a narrow trim ring of scrap material.
In order to prevent this trim ring scrap from remaining with, or in one of the cans, it is customary to force a high-velocity stream of air across the can following the trimming operation. Nevertheless, an occasional trim ring becomes lodged in the can, and remains there during the closure and sealing operations, to be discovered by the consumer when the can is opened. While the number of such defects is extremely small, on the order of less than 00.2% of manufactured composite cans, the inevitable expressions of comsumer concern and concomitant loss of product goodwill represents a substantial economic loss.
There are several prior art patents which suggest techniques for cleaning foreign and undesirable materials from containers during the manufacturing operation.
In U.S. Pat. No. 1,173,255, Eberhart discloses apparatus employing brushes which are moved into the cans in synchronous fashion.
U.S. Pat. No. 2,262,697 to Pearson discloses a metal can cleaning mechanism for removing solder in which the cleaning mechanism is aligned with the can and then rotated through the can for cleaning the internal surface.
Other prior art of interest include: U.S. Pat. Nos. 3,490,404 (Vanderlaan et al); 2,327,986 (Bach); 3,881,436 (Paumier et al); 3,983,729 (Traczyk et al); and 2,295,595 (Gladfelter).
In our prior U.S. Pat. No. 4,185,348, we disclose an apparatus and related method for removing trim rings from composite cans, which apparatus employs two conveyors, across one of which the composite cans are conveyed and with a series of reciprocating plungers engaged within a cam race and mounted on the second conveyor alongside the first conveyor, so as to extend into and out of the composite cans for removing trim rings and other foreign material from the cans.